Patients with diabetes are prone to major foot problems. This is because the foot expresses many of the underlying effects of diabetes, including neuropathy, vascular disease, and diminished response to infection.
As a result of the neuropathy, the foot can develop an ulcer. This happens for two reasons. The first is that the neuropathy causes paralysis of small muscles in the foot, which results in clawing of the toes. Clawing of the toes causes prominence of the metatarsal heads (bones closest to the toe) on the bottom of the foot as well as the knuckles on the dorsum (top) of the foot.